Method of and apparatus for determining the density of materials



June 23, 1942.

W. F. CUMMINS, JR

METHOD OF AND APPARATUS FOR DETERMINING THE DENSITY OF MATERIALS Filed Feb. 11, 1939 I lNVE/k/TOR MZZz'a/rz FCummnsJn HTTVORNEY Patented June 23, 1942 UNITED STATES PATENT OFFICE METHOD OF AND APPARATUS FOR DETER- MINING THE DENSITY OF MATERIALS William F. Cummins, In, Fort geek, Mont. Application February 11, 1939, Serial No.'255,9,04

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) p to determine the percentage of one material in a mixture of two materials flowing through a- 4 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without. the payment to me of any royalty thereon.

This invention relates to a method of and ap paratus for determining the density of materials, particularly it is directed to a method of and apdifierent degrees of inclination and in which equal friction losses occur under the same,condition of flow, thereby eliminating the friction loss factor in determining the density of the fluids or the mixture of fluids and solid particles.

Another object of the invention is to provide a method of and apparatus for determining the percentage of one material in a mixture of two materials flowing through a conduit, when the density of each material in the mixture is known by measuring the difierential pressures between points in equivalent sections of conduit having diflerent degrees of inclination.

In the operation of the pipelines which are used for the transportation of fluids or a mixture of water and solids, for example, as practiced by the pipeline dledge operator, it is desirable to know at all times the density of fluids or the density of a mixture of fluid and solids passing a given station. Without this information as a guide, the amount of solids may become so concentrated that they will, by force ofgravity, drag along the bottom of the pipeline in such a manner as to cause excessive wear in the pipeline and a low output of solids. In addition, a stream when greatly burdened with solids, may at any time, due to a slight change in conditions, plug the line with solid material, thus stopping the operations.

Heretofore the amount of solids flowing through a pipeline was determined in only a straight section of pipe by detecting the velocity of fluids or solids flowing through the pipeline or by the friction loss in the pipeline.

It is therefore the aim and purpose of this invention to provide a method of and apparatus for determining the mean density of materials flow ing in a conduit, which materials may be either conduit by measuring the differential pressure between points in equivalent sections of the conduit having different degrees of inclination, in-

dependent of the velocity of flow of the fluid or' .materials and the amount of friction loss in the conduit. With the above and other objects and advantages in view, the invention consists in certain features of construction and operation of parts which will hereinafter appear, and in which Fig. l is a side elevation of a pipeline-embodying the invention; and

Fig. 2 is an enlarged vertical section of a separating device used in carrying out the invention.

In the illustrated embodiment characterizing the invention I indicates a pipeline which may be a portion of a discharge conduit used in connection. with hydraulic dredge operations and through which fluids or fluids and solids are transported. The pipeline I has a substantially at points 6 and I.

ferential pressure of the fluid or mixture of fluidfluids or a mixture of fluid and. solid particles also horizontal section 2 which is tapped at points 3 and I and another section 5 which is bent at an angle to the horizontal section 2 and tapped A device 8 for measuring difand solid particles flowing in the section 2 of the pipeline I is connected by conduits 9 of equal length to separating tanks I0, one of each of which is in turn connected by a short conduit I6, at one of each of the tapped points 3 and 4 respectively, provided on the section 2 of the pipeline. Another device II for'measuring the differential pressure of the fluid or mixture of fluid and solid'particles flowing in the section 5 of the pipeline is connected by conduits I2 01 equallength, to separating tanks I3, one of each of which is in turn also connected by a short conduit I6, at one of each of the tapped points 6 and I respectively, provided on the section 5 of the pipeline. A fluid of known density is used to fill the conduits 9 and I2, which fluid only transmits pressure to the differential pressure measuring devices. The separating devices In and I3 are used for the purpose of preventing the material which is flowing through the pipeline I from migiifi with the fluid which fills the conduits 9 an The separating devices III for the section 2 of I the conduit I are caused to receive some of the fluid or a mixture of fluids and solid particles of diflerent densities which has been forced into the separating devices III. The density of the fluid or solid particles forced into the separating device I8 'at point I of the section 2 of the conduit being greater than the density of the fluid or mixture of fluids and solid particles which has been forced into the separating device I8 at point 3 of the section 2 and the separating devices I3 are adapted to receive some of the fluid or the mixture of; fluid and solid particles. of different densities at points 8 and l on the section 5 of the conduit I, the density of the portion of fluid or mixture of fluid and solid particles forced into the separating 'device I3 at point 8 of the section 5 of the conduit being greater than the density of the fluid forced into the separating device I3 at point I of the section 5,'because gravity willtend to hold-the fluid or the mixture of fluids and solid particles of greater density at the place where the two sections 2 and 5 are inclined to each other. These separating devices l and I3 are in the form of tanks I4 containing a fluid or mixture I5 of unknown density which fills thetanks to substantially the same height above their points of connections with the' pipeline I, as illustrated in Fig. 2. Small differences in height will introduce only negligible errors in results. In order to allow any air which should enter the tanks .III and I3 to escape into the atmosphere a valved air vent IT is provided in th'e'upper end of the tanks. To clean out the tanks Ill and I3 a plug. I8 maybe inserted'in the bottom thereof. 1'

The introduction of any fluid or mixture of fluid and solid particles into the tanks I8 and I3 4 from -the pipeline I, through the conduits I6 is'not at all necessary as any suitable means, which would prevent the fluid or fluid and solid particles in the pipeline, from entering the conduits -9-and I-2 leading to the differential pressure measuring devices 8 and II would be satisfactory for the purpose intended. The admission of the milder mixture of fluid and solid particles into the tanks III and I3 from the pipeline I, is merely incidental to the operation of the differential pressure measuring devices.

The left and right pressure sides of the difierential pressure measuring devices Band II are The principle of operation depends upon the fact that, in an inclined section of pipeline through which a material is being transported at a uniform velocity, the difference in pressure between two points along the section will. vary with the inclination of the section, the friction loss and with the density of the material between those points. If the sections 2 and 5 of the pipeline I between points 3 and 4 and between points 8 and I have difierent degrees of inclination but are of equal length, diameter and inside surface roughness, and if the velocity distribution is similar in both these sections, the difference between the differential pressure indicated by 8 and by II will depend upon the density of the material flowing in the pipeline I.

After the conduits Band I2 and tanks I8 and I3 are filled, only a slight oscillating flow occurs asthe pressure in the pipeline fluctuates. The conduits 9 and I2 transmitting'pressure only to the difierential pressure measuring devices 8 and I I and since there is no flow through them, the column of fluid such as water in the tanks keep practically all solid particles settled out and the water in the top of the'tanks and in the conduits 9 and I2 remain-practically clear.

If it is desired to measure the mean density of a liquid only, instead of a mixture such as is encountered in dredge pipelines, a liquid 'of known density, which is not miscible with the liquid being measured and which has a density less than that of the lowest density or higher than that of the highest density of the liquid being measured, can be usedin the conduits 9 and IZ-and in the tanks I0 and I3. For .instance, if the liquid flowing in the pipeline I is an aqueous solution, thetop portion of the separating tanks and the-connecting conduits can be filled with a light Oil. If the liquid in the pipeline was some oil which was lighter than indicated by the numerals I9, 20, 2I and 22, re-

spectively. p

The differential pressure measuring'devices 8 and II ma be differential manom'eters, diaphragm gauges, or any other means for measuring the pressure difference between two points. Likewise, either the section 20f pipeline I between points 3 and 4 or the section 5 thereof between points 6 and 1, or both, may be inclined. The inclination of the two'sections 2 and 5 of 'the pipeline I, relative to each other must be such that the devices 8 and II will indicate'differential pressures, which differ from each other by an' amount sufficient for the density of the material inthe pipeline to be determined with the required degree of accuracy. This is accomplished by inclining the two sections 2 and 5 of the pipeline I a sufiicient amount with respect to eachother, such that the points of connections of the conduits 9 abut the section Zof the pipeable'the densities of the material flowing in the pipeline I to be determined with the desired j degree of accuracy.

necting conduits 9 and I2. If a mixture of solid particles with a fluid of known density, such as water, is being transported, and if the specific gravity of the solid particles is known, the percentage of solids in the mixture can be determined. This is of use in connection with the operation of, pipeline dredges and other systems where the solids are mixed with water and transported through pipelines.

Referring to Fig. l, assume the direction of flow in' pipeline .I to be tothe right in the direction of the arrows, and let- 1 h4=diflerence in elevation of point 20 and point likewise let m1=pressure on side of differential pressure measuring instrument II connected to point 6 Pzz=pressure on side of differential pressure measuring instrument II connected to point I m=pressure in pipeline at point I hs=difierence in elevation of point 2 I and point i hq=difierence in elevation of point 22- and point I;

also let knowing the distances ha, 714, he and M, and also the density of the fluid in conduits 9 and I2, the

densityof d1 of the material flowing through the pipeline I can be determined from the readings of the devices 8 and I] which show the differential pressures (1021-1 22) and (pm-P20).

It will thus be seen that there is provided a highly useful and novel method of and apparatus for determining the density of materials or a mixture 'of materials transported through pipeline or other conduits. Even though there has been herein described certain features of construction and operation of parts, it is nevertheless to beunderstood that various changes may be made therein without departing from the spirit or scope of the invention.

Having described my invention, what I claim as new and wish to secure by Letters Patent is:

1. In an apparatus for determining the mean density of a fluid or a mixture of fluids and solid particles flowing in a pipe line, the combination of a pipe line including equivalent sections in which equal friction losses occur under the same conditions of flow, said sections having different degrees of inclination, differential pressure measuring devices, one of each of. said diflerential pressure measuring devices being connected at spaced points between an equivalent portion of one of each of said sections, the points of connection of one of said pressure measuring devices, with one of said sections being at a different elevation than the points of connection of another of said pressure measuring devices with another of said sections.

2. The method of determining the mean density of fluids or of mixtures of fluids and solid particles flowing in a conduit including equivalent sections at an angle to each other and in which equal friction losses occur under the same V condition of flow, which consists of simultaneously measuring the differential pressure of the fluids or of the mixtures of fluids and solid particles between spaced points at one elevation in one of said sections of the conduit and between spaced points at a different elevation in another of said sections of the conduit and computing the mean density of the fluids or mixtures of fluids and solid particles flowing through the conduit from the differential pressures measured.

3. Inan apparatus for determining the mean density of a fluid or of a mixture of fluids and solid particles flowing in a pipeline including two equivalent sections at an angle to each other and in which equal friction losses occur under the same conditions of flow, tanks mounted at spaced-points on one of said equivalent sections of the pipeline and tanks mounted at spaced points on the other of said equivalent sections of the pipelingsaid tanks adapted to receive portions of said fluid or mixture of fluids and solid particles, flowing through said pipeline, a differential pressure measuring device connected in communication with the tanks on one of said sections of the pipeline and a differential pressure measuring device connected in communication with the tanks on the other of said sections I of the pipeline.

4. In an apparatus for determining the mean density of fluids or ofa mixture of fluids and solid particles flowing in a pipeline including two equivalent sections at an angle to .each other and in which equal friction losses occur under the same conditions of flow, tanks connected at spaced points on one of said sections of said pipeline and tanks connected at spaced points on the other of said sections of the pipeline, differential pressure measuring devices, one of said differential pressure measuring devices having connections with said tanks on one of said sections of the pipeline and another of said differential pressure measuring devices having connections with the tanks on the other of said sections of the pipeline, the points of connection of said tanks on one of said sections being of a diiferent elevation than the points of connection of the tanks on the other of said sections of the pipeline.

- WILLIAM F. CUMMINS, JR. 

